1. Field of the Invention
The present disclosure relates to a development device to be used in an electrophotographic image forming apparatus, and a process cartridge to be detachably mounted to the electrophotographic image forming apparatus.
Here, the electrophotographic image forming apparatus is an apparatus for forming an image on a recording material by employing electrophotographic image forming processing. The electrophotographic image forming apparatus includes, for example, an electrophotographic copying machine, an electrophotographic printer (for example, a laser light printer and a light-emitting diode (LED) printer), and a facsimile apparatus.
The process cartridge is formed by integrally combining a charging unit, a development unit or a cleaning unit and an image bearing member into a cartridge so as to be detachably mounted to an apparatus main body of the electrophotographic image forming apparatus. Specifically, the process cartridge includes at least a development unit and an image bearing member integrally combined so as to be detachably mounted to the apparatus main body.
2. Description of the Related Art
In an electrophotographic image forming apparatuses employing an electrophotographic process, a process cartridge system has been employed in which an electrophotographic photosensitive drum and a process unit acting on the electrophotographic photosensitive drum are integrally combined into a cartridge to be detachably mounted to an apparatus main body. The process cartridge system enables a user to perform maintenance of the apparatuses without relying on a service person. Thus, the operability can be significantly increased. Consequently, the process cartridge method has been widely used in the electrophotographic image forming apparatuses.
In the process cartridge system, to enable a user to smoothly replace the cartridge, generally, a developer remaining amount detection function for detecting a remaining amount of a developer and displaying the detection result for the users is provided. As a developer remaining amount detection method, a light-transmission type developer remaining amount detection method has been widely employed. In this method, a light emitting element such as an LED and a light receiving element such as a phototransistor which are attached to an image forming apparatus main body form a light path passing through a developer storage chamber. Based on a time period the developer blocks the light path, a remaining amount of the developer is detected (Japanese Patent Application Laid-Open No. 2001-318524).
A development device discussed in Japanese Patent Application Laid-Open No. 2010-9021 employs a structure in which a cleaning unit cleans a light transmission member through which detection light passes to increase a detection accuracy in the light-transmission type developer remaining amount detection. In this structure, a conveyance unit provided to a rotating shaft member conveys a developer in a developer storage chamber in a direction of a development roller, and the cleaning unit follows the rotation of the conveyance unit to rub and clean the light transmission member.
In such a conventional development device described above, a part of the developer, which is not conveyed by the conveyance unit and remains on an upstream side of the conveyance unit and on a downstream side of the cleaning unit, is conveyed by adhering to a surface of the cleaning unit. If a large amount of the developer adheres to the surface of the cleaning unit, the developer may prevent the cleaning unit from rubbing and cleaning the light transmission member. The prevention of the cleaning of the light transmission member by the cleaning unit may decrease the detection accuracy in the developer remaining amount detection.